Dual fuel apparatus for heaters



June 19, 1956 M. M. REUTER DUAL FUEL. APPARATUS FOR HEATERS Filed Oct. 17, 1952 INVENTOR;

. fl gMF-BUTER.

United States Patent DUAL FUEL APPARATUS FOR HEATERS Malvern M. Renter, Columbus, Ohio, assignor to Surface Combustion Corporation, Toledo, Ohio, a corporation of Ohio Application October 17, 1952, Serial No. 315,335

1 Claim. (Cl. 158-406) This invention relates to burner apparatus for burning either of two alternate gaseous fuels, generally known as dual fuel burner apparatus.

Considerable difliculty is generally experienced in providing for simple change-over between natural gas and propane, for example, without extensive modification of the burner equipment. In providing permanent fuel manifold and nozzle apparatus for both fuels, ditficulty is experienced in providing proper alignment and efficiency of the nozzles while maintaining ease of constructing and servicing the equipment.

For a consideration of what I believe to be novel and my invention, attention is directed to the following portion of this specification, and the drawing and concluding claim thereof.

In the drawing:

Fig. 1 is a partial sectional View of a fuel fired space heater embodying this invention.

Fig. 2 is a view of the dual fuel manifold and nozzle assembly in the heater of Fig. 1.

Fig. 3 is a sectional view of the assembly of Fig. 2.

Figs. 4, 5, 6 and 7 show modifications of the assembly of Figs. 2 and 3.

Referring to the drawing, the heater comprises a heat exchanger 19 for transferring heat from combustion gases to air, a burner 11 for supplying combustion gases to the heat exchanger, a frame 12 for supporting the burner and heat exchanger, a casing 13 about the heater, and a fuel supply manifold 14. A heater of the type shown will ordinarily comprise several burners assembled on front and rear frame members 13 and 16, and in the heater the rear frame member 16 is supported on the frame 12 and the front frame member is supported by pins 17 on the fuel manifold casting 14, the pins passing through suitable holes provided therefor in the front frame member 15. The manifold 14 is supported on frame 12 in the heater by ears 20 at either end of the casting. A sliding primary air shutter 21 is provided for each burner 11 so that adjustments may be easily made without disturbing the fuel nozzle or burner, the relative positions of which are fixed by the support pins 17, and rear frame member 16.

The dual fuel manifold casting is provided with two plenum chambers, one for each of two fuels such as propane and natural gas, and first and second fuel inlets 22 and 23 respectively, therefor. A multiplicity of propane gas nozzles 26 are screwed into holes provided therefor in the internal dividing wall 24 adjacent the propane plenum chamber, the nozzles 26 having externally threaded portions extending through holes in the wall 25 of the natural gas plenum chamber and towards the primary air shutters of the burners. The nozzles 26 are suitably drilled to provide the desired discharge orifice for the gas in the first plenum chamber, in this case propane. A series of secondary nozzles, internally threaded to screw over the propane nozzles, are provided with a ring or circular series of orifices adapted to discharge natural gas into the same air shutter and burner as the central propane nozzle. The casting is spot-faced or gasketed about the nozzle receiving portion of the wall 25 so that by turning 2,750,997 Patented June 19, 1956 the natural gas nozzle tight at gas tight seal is eifected as the nozzle becomes wedged against the wall 25, and natural gas nozzles are provided concentric with the pro pane nozzles without such mechanical problems as would appear if an annular orifice for natural gas were to be formed. The axial alignment tolerances for the respective holes in the walls 24 and 25 are thus much greater, providing for ease of manufacture and at no sacrifice in accuracy of alignment of the gas nozzles with the burners.

In Fig. 4 the nozzle arrangement is modified by forming the respective holes in walls 24 and 25 by a single tapered reamer and using a single nozzle 31 machined from a tapered plug with a central passage for propane gas and a circular series of natural gas passages connecting with the natural gas plenum chamber at a machined off-set in the plug. The plug is preferably made with a threaded portion near the discharge side of the plug and a hex head for turning the plug into a threaded boss of the wall 25, thus driving the tapered plug into the respective tapered holes in the walls 24 and 25, making gas tight seals.

in Fig. 5 a modified nozzle arrangement is shown wherein the manifold structure of Figs. 2 and 3 is modified to provide threads only in wall 24, and a single piece nozzle 25 is screwed thereinto until its rim seats on the boss on wall 25, providing gas tight seals at each wall.

Fig. 6 differs from Fig. 5 in that a drilled boss 33 on wall 24 extends toward the hole in wall 25, and a unitary orifice plate 34 is threadedly secured to the boss on wall 25 and is turned until a central portion comes to rest on the central boss 33.

Fig. 7 shows a structure similar to Fig. 6 except that the bosses on walls 24 and 25 are spot-faced in a single operation to the same plane, and an orifice disc 35 is then secured by screws 36 to the manifold 14.

Each modification provides a circular series of fuel ports for natural gas and a central fuel port for propane, or such fuels as may be desired, and a threaded joint between the nozzle and one wall is utilized to provide a pressure seal on the other wall due to the wedging action of the appropriate screw thread.

I claim:

In burner apparatus, in combination: wall means forming first and second longitudinally extending fuel chambers including a dividing wall between said chambers and a second wall bounding the second fuel chamber and each of said walls having a longitudinally extending series of apertures therein with each aperture in the dividing wall axially aligned with an aperture in the second wall; a series of nozzles disposed in the apertures and forming axial fuel discharge ports from the first fuel chamber through each nozzle and a plurality of fuel discharge ports from the second fuel chamber in a circular series around each of said axial fuel discharge ports; a plurality of entraining tubes for receiving streams of fuel gas and air entrained therewith and delivering the gas-air mixture so formed to burner ports; means for securing said entraining tubes in parallel relation to each other and each aligned with one of said axial fuel discharge ports to receive fuel from said ports or from the ports in the circular series thereabout; means for supplying a first fuel to the first fuel chamber; and means for supplying a second gas to the second fuel chamber.

References Cited in the file of this patent UNITED STATES PATENTS 408,073 Bell July 30, 1889 1,204,359 Kemp et a1. Nov. 7, 1916 1,838,903 BushoW Dec. 29, 1931 2,582,582 Bottom Jan. 15, 1952 2,658,569 Hughes et al Nov. 10, 1953 

